Prediction method for valve clearance adjustment equivalent mileage

Abstract

The invention discloses a method for predicting equivalent mileage of valve clearance adjustment, which comprises the following steps of: performing a reliability test on an engine, and determining reliability time T of valve clearance adjustment according to recorded detection data of a valve before and after the reliability test; the method comprises the following steps: acquiring road spectrum fuel consumption K per hundred kilometers under a comprehensive working condition through a road test, acquiring reliability test average hour fuel consumption k recorded by a rack test, and calculating reliability per hour equivalent road spectrum mileage D = k / K * 100 through an equal fuel consumption method; obtaining the average rotating speed N of the engine under the comprehensive working condition through a road test, obtaining the average rotating speed n of the reliability test cycle working condition through a bench test, and calculating an acceleration factor R = n / N; the whole vehicle valve clearance adjustment equivalent mileage S is equal to T * D * R. According to the method, the whole vehicle road test is associated, and the adjustment mileage of the whole vehicle valve clearance is effectively evaluated and predicted through equivalent operation and acceleration factor calculation.

Description

Technical Field

[0001] The invention belongs to the technical field of engine control, and in particular relates to a method for predicting equivalent mileage of valve clearance adjustment. Background Art

[0002] The valve mechanism is generally composed of camshafts, rocker shafts, valve rocker arms, valve springs, valve guides, valves, valve stem oil seals, valve seat rings and other parts. Its main function is to open and close the intake and exhaust valves in time according to the working order and valve timing of each cylinder of the engine to complete the ventilation process, and to ensure the sealing of the cylinder during the compression stroke and the power stroke. The engine is at high temperature when working, and a gap needs to be reserved between the valves and their transmission parts to avoid the thermal expansion of valves and other parts causing the gap to be too small, and the valve cannot be completely closed, which in turn affects the sealing of the cylinder. However, during the long-term operation of the engine, the relevant parts of the valve mechanism will be worn, resulting in excessive valve clearance, causing the valve to open late and close early, the valve opening is insufficient, the inflation is insufficient, and the exhaust is not smooth, which affects the engine power, and at the same time increases the impact load of the matching parts and aggravates the wear of the relevant parts of the valve mechanism. In particular, during the user's use of the whole vehicle, the valve clearance needs to be adjusted to avoid abnormal engine performance caused by too small or too large valve clearance, resulting in customer complaints. Therefore, predicting and evaluating the valve clearance adjustment cycle in the market, setting a reasonable valve clearance adjustment cycle in advance, and reasonably reminding users to perform maintenance can improve customer satisfaction.

[0003] At present, the evaluation method for the valve clearance adjustment cycle is mainly such as patent application number CN201911352191.7, which discloses a method and system for evaluating the valve clearance adjustment cycle. The variation range of the valve clearance is determined by experiments, and based on the variation range, the change of the valve clearance over time during engine operation is fitted with data to construct a valve clearance variation model. The variation model is the variation law of the engine during operation, and the current valve clearance of the engine is obtained. When the valve clearance meets the variation range, no adjustment is required. When the valve clearance does not meet the variation range, adjustment is required. The adjustment cycle of the valve clearance is determined according to the variation law of the valve clearance, so that the engine is always in a good operating state and the performance is improved.

[0004] However, the above-mentioned prior art has the following defects: adjustment is only made based on experimental data without considering actual driving conditions and the influence of the wear mechanism of the valve mechanism on the valve clearance mileage, which will lead to inaccurate adjustment cycles and may cause excessive or insufficient maintenance. It is impossible to accurately predict the changes in the valve clearance of the vehicle in actual use, which will have an adverse effect on the performance, fuel consumption, emissions, reliability and service life of the engine, and may even cause safety hazards.

[0005] The information disclosed in the above background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] The purpose of the present invention is to provide a method for predicting the equivalent mileage of valve clearance adjustment, which is associated with vehicle road tests and combined with the wear mechanism of the valve mechanism. Through equivalent operations and acceleration factor calculations, the method can evaluate and predict the adjustment mileage of the valve clearance of the whole vehicle, set a reasonable valve clearance adjustment period in advance, and reasonably remind users to perform maintenance, thereby improving customer satisfaction and enhancing product competitiveness.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for predicting equivalent mileage of valve clearance adjustment comprises the following steps:

[0009] S1: Perform a reliability test on the engine, and determine the reliability time T of valve clearance adjustment based on the recorded valve test data before and after the reliability test;

[0010] S2: Obtain the fuel consumption K of the road spectrum per 100 kilometers of the comprehensive working condition through road tests, and obtain the average hourly fuel consumption k of the reliability test recorded by the bench test, and calculate the reliability equivalent road spectrum mileage D = k / K*100 per hour through the equal fuel consumption method;

[0011] S3: Obtain the average engine speed N of the comprehensive working condition through road test, obtain the average engine speed n of the reliability test cycle working condition through bench test, and calculate the acceleration factor R=n / N;

[0012] S4: Based on the calculated reliability time T of valve clearance adjustment, reliability equivalent road spectrum mileage per hour D and acceleration factor R, the equivalent mileage of valve clearance adjustment of the whole vehicle is obtained as S=T*D*R.

[0013] Specifically, in step S1, the valve detection data recorded before and after the reliability test includes:

[0014] Before the reliability and durability verification test, record the valve clearance a and valve sinking amount b;

[0015] After reliability, check valve clearance A and valve sinking amount B;

[0016] The maximum value H of the valve clearance that does not affect the normal operation of the engine verified by the test;

[0017] The minimum value h of valve clearance that does not affect the normal operation of the engine verified by the test;

[0018] The maximum valve sinking amount C allowed by the design.

[0019] Specifically, in step S1, the reliability time T of valve clearance adjustment is determined based on the recorded valve detection data before and after the reliability test, including: if the valve sinking amount after the reliability test exceeds the limit valve sinking amount allowed by the design, that is, B≥C, and the engine performance is normal and passes the reliability verification, then regardless of whether the valve clearance after the reliability test exceeds the valve clearance limit, the reliability verification time Y is set as the reliability time T of valve clearance adjustment, that is, T=Y.

[0020] Specifically, in step S1, the reliability time T of valve clearance adjustment is determined based on the recorded valve detection data before and after the reliability test, including: if the valve sinking amount after the reliability test does not exceed the limit valve sinking amount allowed by the design, that is, B<C, the valve clearance after the reliability test exceeds the valve clearance limit, and the engine performance is normal, and the reliability verification is passed, the reliability verification time Y is also set as the reliability time T of valve clearance adjustment, that is, T=Y.

[0021] Specifically, in step S1, the reliability time T of the valve clearance adjustment is determined according to the recorded valve detection data before and after the reliability test, including: if the valve sinking amount after the reliability test is within the limit valve sinking amount required by the design, and the valve clearance after the reliability test is within the limit, that is, B<C, h<A<H, then continue the reliability verification and make the following judgments:

[0022] When the valve sinking reaches the limit valve sinking allowed by the design first, and the valve clearance is still within the limit requirement, the reliability time of valve clearance adjustment is the equivalent time when the change of valve sinking reaches the limit valve sinking allowed by the design, that is, T1 = C / B*Y;

[0023] When the valve sinking amount does not reach the limit valve sinking amount allowed by the design, the valve clearance reaches the maximum valve clearance, and the reliability time of the valve clearance adjustment is the equivalent time for the valve clearance to reach the maximum valve clearance, that is, T2 = (Ha) / (Aa)*Y;

[0024] When the change in valve sinking amount does not reach the limit value and the valve clearance reaches the minimum valve clearance, the reliability time of valve clearance adjustment is the equivalent time for the valve clearance to reach the minimum valve clearance, that is, T3 = (ah) / (aA)*Y;

[0025] The reliability time of valve clearance adjustment is T=MIN(T1, T2, T3).

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. This technical solution comprehensively considers reliability tests, road tests and theoretical calculations. First, the long-term operation of the engine is simulated through bench tests to obtain key data such as valve clearance and valve sinking, which provides a basis for prediction. Secondly, the equal fuel consumption method is introduced to convert the fuel consumption of the bench test into equivalent road mileage, so that the test results are closer to actual use. Finally, the difference between bench tests and actual road driving is considered, and the bench test results are effectively linked to actual road driving conditions, making the prediction results more practical. Finally, the changes in valve clearance are more comprehensively evaluated, so that the mileage of the vehicle that needs valve clearance adjustment in actual use can be more accurately predicted, avoiding excessive maintenance and insufficient maintenance, thereby improving the performance, reliability and durability of the engine and reducing maintenance costs.

[0028] 2. This technical solution takes into account both valve clearance and valve sinking, evaluates the wear state of the valve mechanism more comprehensively, and improves the reliability of prediction. In particular, when the valve sinking exceeds the limit value, even if the valve clearance is still within the limit value, it is determined that adjustment is required, which is more in line with actual use and avoids potential engine failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the steps of a method for predicting equivalent mileage of valve clearance adjustment according to the present invention.

[0030] Figure 2 The present invention is a flow chart of a method for predicting equivalent mileage of valve clearance adjustment.

[0031] Figure 3 This is a judgment logic diagram of the reliability time of the valve clearance adjustment of the present invention. DETAILED DESCRIPTION

[0032] In order to explain the technical content, purpose and effect of the present invention in detail, the following is an explanation in combination with the embodiments and the accompanying drawings. In the description of this embodiment, it should be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, which are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0033] The technical solution adopted in this embodiment is a method for evaluating and predicting the equivalent mileage of valve clearance adjustment. Figure 1-3 As shown, Figure 2 The data that needs to be collected for the flowchart are as follows:

[0034] 1. Pre-reliability data detection: record valve clearance a and valve sinking amount b before reliability and durability verification test;

[0035] 2. Post-reliability data detection: After reliability, valve clearance A and valve sinking amount B are detected;

[0036] 3. Maximum value of valve clearance: the maximum value H of valve clearance verified by the test that does not affect the normal operation of the engine;

[0037] 4. Minimum valve clearance: the minimum valve clearance h verified by the test that does not affect the normal operation of the engine;

[0038] 5. Valve sinking limit: the maximum valve sinking amount C allowed by design;

[0039] 6. Reliability time of valve clearance adjustment: The reliability time T of valve clearance adjustment is obtained by comparing and analyzing the post-reliability test data with the valve clearance and the limit valve sinking amount allowed by the design;

[0040] 7. Road spectrum fuel consumption per 100 kilometers: The road spectrum fuel consumption per 100 kilometers K collected and input from the vehicle road test;

[0041] 8. Average hourly fuel consumption in reliability test: Average hourly fuel consumption in reliability endurance test k;

[0042] 9. Average speed of road spectrum conditions: the average engine speed N of the vehicle road test conditions;

[0043] 10. Reliability test cycle average speed: the average engine speed n of the reliability endurance test cycle condition;

[0044] 11. Reliability equivalent road spectrum mileage per hour: The road spectrum equivalent mileage D corresponding to the reliability verification per hour calculated by the equal fuel consumption method;

[0045] 12. Acceleration factor: The acceleration factor R of the reliability verification corresponding to the road spectrum test calculated based on the average speed of the road spectrum condition and the average speed of the reliability test cycle;

[0046] 13. Vehicle valve clearance adjustment mileage: The vehicle valve clearance adjustment mileage S is calculated based on the reliability time of valve clearance adjustment, the reliability equivalent road spectrum mileage per hour calculated by the equal fuel consumption method, and the acceleration factor.

[0047] Specifically, the method for evaluating and predicting the equivalent mileage of valve clearance adjustment in this embodiment includes the following steps:

[0048] S1: Perform a reliability test on the engine, and determine the reliability time T of valve clearance adjustment based on the recorded valve test data before and after the reliability test.

[0049] Specifically, the valve test data recorded before and after the reliability test includes:

[0050] Comprehensively consider the adequacy and effectiveness of component verification, set appropriate durability test time and test durability conditions, conduct reliability durability verification on the valve train, record the valve clearance a and valve sinking amount b before reliability, and ensure that the test conditions are normal;

[0051] After the reliability test is completed, check and record the valve clearance A, valve sinking amount B, and check the damage of the valve mechanism;

[0052] The bench test verifies that it does not cause abnormal engine performance, does not lead to failure of the valve mechanism, and has a maximum valve clearance H and a minimum valve clearance h with a certain safety margin.

[0053] Valve clearance and valve depression are key indicators for evaluating the status of the valve mechanism: Valve clearance refers to the clearance between the end of the valve stem and the drive mechanism (such as a camshaft or rocker arm) when the valve is closed. Valve depression refers to the amount of depression caused by wear or deformation of the valve seat on the cylinder head. Changes in these two parameters directly affect the opening and closing of the valve, and thus affect the performance of the engine. Set reasonable limits as the basis for adjustment: In order to ensure the normal operation of the engine, the valve clearance and valve depression need to be controlled within a certain range. Therefore, it is necessary to set the maximum value H and minimum value h of the valve clearance, as well as the limit valve depression C allowed by the design, based on design requirements and test verification. When the valve clearance or valve depression exceeds these limits, it is considered that adjustment is required.

[0054] According to the recorded valve test data before and after the reliability test, the reliability time T of valve clearance adjustment is determined. The judgment logic is as follows: Figure 3 As shown, including:

[0055] According to the test data after reliability, if the valve sinking amount after reliability exceeds the limit valve sinking amount allowed by the design, that is, B≥C, and the engine performance is normal and passes the reliability verification, then regardless of whether the valve clearance after reliability exceeds the valve clearance limit, the reliability verification time Y is set as the reliability time T of valve clearance adjustment, that is, T=Y;

[0056] Similarly, if the valve sinking amount after reliability does not exceed the limit valve sinking amount allowed by the design, that is, B<C, the valve clearance after reliability exceeds the valve clearance limit, and the engine performance is normal, the reliability verification is passed, and the reliability verification time Y is also set as the reliability time T of valve clearance adjustment, that is, T=Y;

[0057] If the valve sinking amount after reliability is within the limit valve sinking amount required by the design, and the valve clearance after reliability is within the limit, that is, B<C, h<A<H, then it can be divided into three situations:

[0058] ①Continue the reliability verification. The valve sinking amount will first reach the limit valve sinking amount allowed by the design. If the valve clearance is still within the limit requirement, then the reliability time of the valve clearance adjustment is the equivalent time when the change of the valve sinking amount reaches the limit valve sinking amount allowed by the design, that is, T1 = C / B*Y;

[0059] ②Continue the reliability verification. If the valve sinking amount does not reach the limit valve sinking amount allowed by the design and the valve clearance reaches the maximum value of the valve clearance, then the reliability time of the valve clearance adjustment is the equivalent time for the valve clearance to reach the maximum value of the valve clearance, that is, T2 = (Ha) / (Aa)*Y;

[0060] ③Continue the reliability verification. If the change in valve sinking amount does not reach the limit value and the valve clearance reaches the minimum value of the valve clearance, then the reliability time of the valve clearance adjustment is the equivalent time for the valve clearance to reach the minimum value of the valve clearance, that is, T3 = (ah) / (aA)*Y;

[0061] Therefore, under this type, the reliability time of valve clearance adjustment is the shortest time among the three cases, that is, T=MIN(T1, T2, T3).

[0062] Compared with the existing technology that simply uses the test time as the adjustment cycle, this method determines the adjustment time more precisely based on the changes in valve clearance and valve sinking, combined with the limit requirements, and is more in line with the actual wear state. In particular, for the case where the valve sinking amount and valve clearance do not reach the limit synchronously, they are calculated and the minimum value is taken respectively, making the prediction more comprehensive.

[0063] S2: Obtain the fuel consumption K per 100 kilometers of the comprehensive working condition through road tests, and obtain the average hourly fuel consumption k of the reliability test recorded by the bench test, and calculate the reliability equivalent road spectrum mileage D = k / K*100 per hour through the equal fuel consumption method.

[0064] This step links the bench test results with actual road driving conditions. Through the equal fuel consumption method, the fuel consumption of the bench test is converted into equivalent road driving mileage, making the bench test results more practical, easier to understand and apply. Compared with directly using the bench test time to predict the adjusted mileage, the introduction of the equal fuel consumption method improves the accuracy of the prediction.

[0065] S6: The average engine speed N of the comprehensive working condition is obtained through road tests. The engine speed can be monitored and averaged by the ECU. The average speed n of the reliability test cycle condition is obtained through bench testing. Considering the influence of speed shock on the wear of the valve mechanism, the acceleration factor R=n / N is calculated.

[0066] By comparing the average speeds of the bench test and the road test, the accelerated wear effect of the bench test on the valve train can be evaluated. This step quantifies the severity of the bench test relative to actual road driving. Compared with simply using the test time for equivalence, the introduction of the acceleration factor takes into account the effect of speed shock on valve train wear, improving the accuracy of the prediction.

[0067] S7: Based on the reliability time T of valve clearance adjustment, the reliability equivalent road spectrum mileage D per hour and the acceleration factor R calculated in the previous steps, further calculate the vehicle valve clearance adjustment mileage S = T*D*R, and take the vehicle valve clearance adjustment mileage S as the valve clearance adjustment equivalent mileage.

[0068] Although the present invention has been described in detail above with specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for predicting equivalent mileage of valve clearance adjustment, characterized in that: The steps include: S1: Perform a reliability test on the engine, and determine the reliability time T of valve clearance adjustment based on the recorded valve test data before and after the reliability test; S2: Obtain the fuel consumption K of the road spectrum per 100 kilometers of the comprehensive working condition through road tests, and obtain the average hourly fuel consumption k of the reliability test recorded by the bench test, and calculate the reliability equivalent road spectrum mileage D = k / K*100 per hour through the equal fuel consumption method; S3: Obtain the average engine speed N of the comprehensive working condition through road test, obtain the average engine speed n of the reliability test cycle working condition through bench test, and calculate the acceleration factor R=n / N; S4: Based on the calculated reliability time T of valve clearance adjustment, reliability equivalent road spectrum mileage per hour D and acceleration factor R, the equivalent mileage of valve clearance adjustment of the whole vehicle is obtained as S=T*D*R.

2. The method for predicting equivalent mileage of valve clearance adjustment according to claim 1, characterized in that: In step S1, the valve detection data recorded before and after the reliability test includes: Before the reliability and durability verification test, record the valve clearance a and valve sinking amount b; After reliability, check valve clearance A and valve sinking amount B; The maximum value H of the valve clearance that does not affect the normal operation of the engine verified by the test; The minimum value h of valve clearance that does not affect the normal operation of the engine verified by the test; The maximum valve sinking amount C allowed by the design.

3. The method for predicting equivalent mileage of valve clearance adjustment according to claim 2, characterized in that: In step S1, the reliability time T of valve clearance adjustment is determined according to the recorded valve detection data before and after the reliability test, including: If the valve sinking amount after reliability exceeds the limit valve sinking amount allowed by the design, that is, B≥C, and the engine performance is normal and passes the reliability verification, then regardless of whether the valve clearance after reliability exceeds the valve clearance limit, the reliability verification time Y will be set as the reliability time T of the valve clearance adjustment, that is, T=Y.

4. The method for predicting equivalent mileage of valve clearance adjustment according to claim 2, characterized in that: In step S1, the reliability time T of valve clearance adjustment is determined according to the recorded valve detection data before and after the reliability test, including: If the valve sinking amount after reliability does not exceed the limit valve sinking amount allowed by the design, that is, B<C, the valve clearance after reliability exceeds the valve clearance limit, and the engine performance is normal, the reliability verification is passed. The reliability verification time Y is also set as the reliability time T of valve clearance adjustment, that is, T=Y.

5. The method for predicting equivalent mileage of valve clearance adjustment according to claim 2, characterized in that: In step S1, the reliability time T of valve clearance adjustment is determined according to the recorded valve detection data before and after the reliability test, including: If the valve sinking amount after reliability is within the limit valve sinking amount required by the design, and the valve clearance after reliability is within the limit, that is, B<C, h<A<H, then continue the reliability verification and make the following judgments: When the valve sinking reaches the limit valve sinking allowed by the design first, and the valve clearance is still within the limit requirement, the reliability time of valve clearance adjustment is the equivalent time when the change of valve sinking reaches the limit valve sinking allowed by the design, that is, T1 = C / B*Y; When the valve sinking amount does not reach the limit valve sinking amount allowed by the design, the valve clearance reaches the maximum valve clearance, and the reliability time of the valve clearance adjustment is the equivalent time for the valve clearance to reach the maximum valve clearance, that is, T2 = (Ha) / (Aa)*Y; When the change in valve sinking amount does not reach the limit value and the valve clearance reaches the minimum valve clearance, the reliability time of valve clearance adjustment is the equivalent time for the valve clearance to reach the minimum valve clearance, that is, T3 = (ah) / (aA)*Y; The reliability time of valve clearance adjustment is T=MIN(T1, T2, T3).

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